I will be hanging them on a (brick + plaster) party wall of my terraced property (UK).

I believe my options are to use either of the following:

Rawl plugs

Masonry self-tapping screws

However I am only aware of the latter due to googling for a solution, and I am unsure if either come in sizes suitable for my needs (The screw holes are 4mm in diameter, I am not sure how deep I should drill)

It's a coat hook - it doesn't hold that much weight, and all the force is shear force, not pulling force.

So pretty much anything will work. Simple plastic anchors with screws will work just fine. (Never heard of rawl plugs but google says that that's the same thing as a plastic anchor.)

Masonry screws are a real pain to use if you are not a pro. I would not use those - if you don't get the hole perfect they won't hold. You have to keep the drill very straight and not let it shake and enlarge the hole.

A potential problem: If the plaster is thick make sure the screws are long enough.

Do you have a hammer drill? You'll need one. Practice first on some non-visible concrete or masonry. It can be hard to drill straight, and not drift from your target with one.

Thank you for your interest in this question.
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